Bending machine for wire or strip

ABSTRACT

The invention is concerned with a bending machine for wire or strip in which the raw material is advanced through the machine step by step and, between each step, a bend is made by a mobile bending tool. The bending tool is retractable from a working position on one side of the path of advance of the material, moveable to the other side of the path without intersecting the path and advancable into a working position on the other side of the path of the advance of the material, so that the tool may be used for bending the material selectively in either direction out of the path of the advance of the material.

, 82 4 July 16, 1974 United States Patent Ritter et al.

[ BENDING MACHINE FOR WIRE R STRIP [75] Inventors: Josef Ritter; Hans Giitt; Klaus 3,184,949 /1965 72/307 3,245,433 4/1966 Taylor, Jr. 140/102 FOREIGN PATENTS OR APPLICATIONS Ritter; Otto Gamillscheg; Wilhelm Boyer; Gerhard Ritter, all of Graz, Austria [73] Assignee: EVG Entwicklungs-u.

925,404 3/1955 Germany............................140/105 Primary Examiner-Lowell A. Larson Verwertungsgesellschaft b ]-1 Attorney, Agent, or Firm-Ernest F. Marmorek Graz, Austria Jan. 11, 1973 [57] ABSTRACT The invention is concerned with a bending machine for wire or strip in which the raw material is advanced 22 Filed: 1

App]. No.: 322,878

through the machine step by step and, between each step, a bend is made by a mobile bending tool. The bending tool is retractable from a working position on Foreign Application Priority Data Apr. 12, 1972 one side of the path of advance of the material, moveable to the other side of the path without intersecting 140/105, 72/307 v[51 1m. B21f 1/00 the p and advancable into a w g Position on 140/102 '1()4, 72/307 the other side of the path of the advance of the mate- I rial, so that the tool may be used for bending the ma- [58] Field of Search [56] References Cited UNITED STATES PATENTS terial selectively in either direction out of the path of the advance of the material. a

6 Claims, 9 Drawing Figures 1| I m fw e. l o a ll lzll o 1. i 1 al liq 6 2 Y 0 a v A/ W PATENTEB JUL 1 61974 SHEI 5 OF 5 FlG.Ia

FIG.7

. I 1 BENDING MACHINE FOR WIRE OR STRIP The invention relates to a machine for bending wire or strip and comprising means for intermittently advancing raw material for bending step by step, the length of each step being the desired distance between each two successive bends, and an intermittently driven mobile bending tool which bends the wire or strip through the desired angle. around a stationary a'nvil after each step of advance. The working stroke of the bending tool is preferably adjustable. Bending machines of this kind are used in particular inthe manufacture of vwire hoops for use in reinforced concrete.

The known bending machines are capable of making bends in only one direction, that is to say it is not possible to bend the wire or strip at a first bending location in the one direction and then, after advancing the wire or strip one step, make a bend in the opposite direction at a second location on the wire or strip; Nevertheless this requirement often occurs. in principle it would be possible to solve the problem by providing two stationary bending anvils situated on opposite sides of the path of advance of the wire or strip, each stationary bending anvil cooperating with itsown'mobile bending tool. An arrangement of this kind would however be costly in construction due to the necessity of providing a driving 7 mechanism which can be coupled selectively to the one or to the other of the two mobile bending tools so as to obtain the desired changes in bending directions.

The aim in the present invention is to avoid these difficulties by providing a bending machine with which bends can be made in opposite directions, relative to the path of advance of the wire or strip, without it being necessary to couple the driving mechanism alternately to two different bending tools. The problem is solved according to the invention in that a single bending tool is arranged to bend the wire or strip selectively in either of two opposite bending directions, away from the path of advance of the wire or strip, and the bending tool is mounted so that it is retractable from a working position on one side of the path and movable to the other side of the path, without intersecting the path, and then advanceable to a working position on the other side of the path. g

It will be observed that the single mobile bending tool remains constantly connected to the driving mechanism, the direction of bending being changed-merely by changing between the forward and return strokes of the drive for making the bend.

Two stationary bending anvils may be positioned one on each side of the path of advance of the wire or strip, the bending tool cooperating selectively with the one or the other of the two stationary anvils for bending the wire or strip in the one direction or the other.

In this case the bending tool can be mounted on a crank which oscillates about an axis which intersects the path of advance of the wire or strip, the two stationary anvils being positioned symmetrically, one on each side of the path. The axle shaft of the crank supporting the mobile bending tool can be a sliding hollow shaft which slides in a direction perpendicular to the path of advance of the wire or strip. During the shift in position of the bending tool from the one side to the other of the path of advance of the wire or strip, the sliding hollow shaft retracts the bending tool transversely so that the bending tool can bypass the path of advance of the wire or strip, without colliding with the wire or strip which The anvil is also mounted so that it can be shifted in position from one side of the path of advance of the wire or strip to the other side, the anvil also bypassing the path ofadvance of the wire or strip, during the shift, by retracting transversely out of the way. The bending anvil and the bending tool are preferably both mounted on a common link which pivots, for the purpose of shifting the anvil and the tool to the other sides of the path of advance of the wire or strip, for changing the direction of the bend, on an axis intersecting the path, the link swinging around about the anvil, after the manner of a crank, for making the bend.

Several examples of machines constructed in accordance with the invention are illustrated in the accompanying drawings, in which:

FIG. 1 is a diagrammatic side view of one machine;

FIG. 1a shows a variant of a detail;

FIG. 2 isa modified end view of the adjustable driving mechanism of the machine shown in FIG. 1, the drawing being modified by stretching it out in the direction of the arror P so as to show more clearly the relative positions of the individual parts,'without the parts overlapping each other in a confusing way;

vFIG. 3 illustrates the arrangements for moving the mobile bending tool and the ejector rod sideways, that is to say transversely with respect to the conveying path forthe wire or strip material;

FIG. 4 is an end view showing a modified driving mechanism;

FIG. 5 is an end view corresponding to FIG. 2, but

shows the modified driving mechanism of FIG. 4;

FIGS. 6 and 7 represents diagrammatically the principles used in several possible versions of the invention; and,

FIG. 8 represents diagrammatically a version of the bending mechanism based on the arrangement shown inFIG.7.

In FIG. 1 wire 1, which is to be converted into bent hoops, passes between two pairs of conveying rollers 2, 2a and 3, 3a which feed the wire through the machine by frictional grip.

roller 11. The endless chain 10 passes over further sprocket wheels fixed to the conveying rollers 2, 2a and 3, 3a. The driving mechanism ensures that when the coupling is engaged drive is transmitted from the electric motor 4 to the pairs of conveying rollers 2, 2a and 3, 3a.

Consequently whenever the coupling is engaged, coupling the flywheel 6 to the gearwheel 7, the wire is advanced through the machine. The advancing of the 4 wire continues until the desired length of wire has been fed through the machine, whereupon the coupling is contact with the upper surface of the wire. The amount of spring thrust applied is adjustable by means of screw threaded spindles 12, 13. After leaving the conveying rollers 2, 2a and 3, 3a the wire 1 passes through a straightener 14 of the known kind, which straightens the wire. Downstream of the straightener 14 there is a rotary friction-driven drum 15 mounted to pivot about an axis 16. The drum is thrust against the surface of the wire by a spring. The rotary drum l drives a pulse sender for an electronic length-measuring device of the kind described in Pat. application Ser. No. 210.824 filed Dec. 22, .1971 which automatically controls the advancing of the wire and the cutting off of the desired lengths by the shears.

Downstream of the friction-driven drum the wire passes through a shears consisting of a stationary shear blade 17 and a mobile blade 18, which cuts off the desired lengths of wire. Downstream of the shears the wire reaches the bending device proper which consists essentially, in the present example, of two stationary bending anvils 19, 19a and a mobile bending toll 20.

The drive for the bending tool 20 is arranged as follows. An electric motor 21 transmits drive through a V-belt or the like to a flywheel 23 which can be coupled, by means of a coupling which is not shown in the drawing, to a gearwheel 24.

The gearwheel 24 is permanently engaged with a gearwheel 25 to the shaft of which is fixed an eccentric 26 which, acting through a connecting rod 27, applies an oscillating motion to a double pivot bearing 37 on which are pivoted the lower ends of a driving link 28 and an idle link 29.

As shown with greater clarity in FIG. 2, and as described in Austrian Pat. application No. A 3181/72, the upper end of the idle link 29 is pivoted at 33'to the upper part of an adjustment link 30 whose lower end is pivoted in a stationary bearing 31. The upper end of the adjustment link 30 is adjustable in position by means of an adjustment spindle 32, the adjustment link 30 pivoting during the adjustment movement in its lower stationary bearing 31. The upper end of the driving link 28 is pivoted at 34 to one arm of a 2-armed rocker which rocks in a stationary rocker bearing 7 36. In regard to dimensions, it should be observed that the effective length of the driving link 28, that is to say the distance between its two pivots 34 and 37, is equal to the effective length of the idle link 29, that is to say the distance between its two pivots 33 and 37.

The linkage system described above makes it possible to adjust the angular movement of the rocker 35 steplessly all the way between 0 and a constructionally predetermined upper limit, during each half-rotation of the eccentric 26 through 180. In the limiting case in which the adjustment spindle 32 has been actuated so as to advance the adjustment link 30 until the two pivots 33 and 34 coincide, rotation of the eccentric 26 merely swings the two links 28 and 29 around together about the coincidence point, no movement being given to the rocker 35.

On the other hand when the adjustment spindle 32 has been actuated so as to pivot the adjustment link 30 in its stationary bearing 31 into a different position, so that the pivot points 33 and 34 no longer coincide, rotation of the eccentric 26 swings the idle link 29 about its pivot 33, the driving link 28 rocking the rocker 35 in its stationary bearing 36, the distance between the pivot points 34 and 37 remaining unchanged. The angular movement imparted to the rocker 35, with each half turn of the eccentric 26, is greater than greater the distance between the pivotpoints 33 and 34, up to the constructionally determined limit of the system.

Pivoted to the upper end of the other arm of the 2- armed rocker 35 there is a driving spindle 38 which is adjustable in position longitudinally by means of ascrew thread. The driving spindle 38 connects the rocker 35 to a gearwheel 39 which engages with a gearwheel 40 which is fixed to the mobile bending tool 20 so that rotation of the gearwheel 40 swings the bending tool. Consequently rotation of the eccentric 26, acting through the connecting rod 27 and the driving link 28 and so oscillating the rocker 35 in its'stationary bearing 36, imparts oscillation to the driving spindle 38, the oscillation being transmitted through the gearwheels 39, 40 to the mobile'bending tool 20, which consequently oscillates with the gearwheel 40 about their common axis.

The angle through which the mobile bending tool 20 oscillates is determined by the position given to the adjustment link 30 by actuation of the adjustment spindle 32.

It will be observed that by actuating the adjustment spindle 32 the operator can therefore adjust the bending angle to the desired value, making due allowance if necessary for the different spring constants of wires of different qualities. On the other hand by adjusting the longitudinal position of the screw threaded driving spindle 38 the operator can set the position of rest of the mobile bending tool 20 with precision so as to obtain precisely symmetrical bending tool movements in the two opposite bending directions, with respect to the path of advance of the wire, irrespective of the existing amplitude value which has been set by adjusting the spindle 32. v

The rigid connection between the gearwheel 40 and the bending tool 20 is arranged as follows. The gearwheel 40 is fixed to a hollow shaft 41 to which the bending tool 20 is also fixed. The two parts 40 and 20 therefore cannot move relative to each other, neither axially nor in rotation. The hollow shaft 41 itself is connected through a piston rod 42 to a piston 43 which slides back and forth in a hydraulic cylinder 44. A helical spring 45, surrounding the hollow shaft 41, thrusts at one end against a collar 46 fixed to the hollow shaft and at the other end against a sliding sleeve 47, the

spring thrusting the sleeve, during operation of the bending tool, against the stationary bearing 48 of the hollow shaft 41. The bearing 48 is mounted in the frame of the machine. A pin 49 connects the sleeve 47 with an ejector rod 51 which slides back and forth in the interior of the hollow shaft 41, the pin 49 working in longitudinal slots 50 in the wall of the hollow shaft.

Outward movement of the hollow shaft 41, away from the hydraulic cylinder 44, is limited by a collar 52 fixed to the hollow shaft. The arrangement ensures that the bending tool 20, thrust outwards by the helical spring 45, assumes a definite outermost limiting position determined by contact between the collar 52 and the stationary bearing 48 of the hollow shaft.

The control system for the sliding movement of the hollow shaft 41 is shown in FIG. 3. An electric motor 53 drives an oil pump 54 which sucks oil in through a suction filter 55 from an oil sump 56 and delivers the oil under pressure through a delivery line 57.

The pressure in the delivery line 57 is kept constant by a constant-pressure valve 58. The flow of hydraulic oil is controlled by an electro-hydraulic slide valve 59 and two throttling valves 60. Depending on the position of the slide valve 59, the piston 43 moves towards the right or towards the left, as indicated by the two arrows a and b.

The machinefunctions as follows. Referring to FIG. 1, let it be assumed that wire hoops are to be bent as indicated by the broken lines, all the bends being made in the same direction. By engaging the coupling, which is not shown in the drawing, the gearwheel 24 is coupled to the flywheel 23, the coupling remaining engaged until the eccentric 26 has completed a full revolution through 360, whereupon the coupling is disengaged and the gearwheel 24 is brought to a standstillby the brake, which is also not shown in the drawing. Durng the first half turn of the eccentric 26, through 180, the mobile bending tool is swung, by the driving mechanism 27 to 41, through the arc of its bending movement, the bending angle having previously been adjusted to the desired value by means of the adjustment spindle 32. The bending angle can if desired be adjusted by hand, as represented in FIG. 1. On the other hand if desired powered adjustment can be provided by a positioning motor 61, as indicated in FIG. 1a. During the second half turn of the eccentric 26 the bending tool 20 is returned to its initial position.

When it is desired to reverse the direction of bending, for example from clockwise, as indicated in FIG. 1, to anticlockwise, the change-over is obtained by moving the electro-hydraulic slide valve '59 intov the position straight-through flow." Hydraulic fluid, acting on the left-hand face of the piston 43 pushes the piston towards the right in the cylinder 44, oil expelled from the cylinder flowing back into the oil sump 56. t

The piston 43, moving in the direction of the arrow a, pulls the hollow shaft 41 towards the right, against the influence of the helical spring 45. In this movement the collar 46 fixed to the hollow shaft 41 compresses the spring. The bending tool 20 therefore moves into the position represented in chain lines in FIGS. 2 and 3. ln this position the bending tool is entirely disengaged from the wire 1. With the coupling engaged the electric motor 21 rotates the eccentric 26 through 180, swinging the bending tool 20 around, entirely out. w

of contact with the wire, from its position of rest above the wire into a new position of rest under the wire.

When the eccentric 26 has completed its rotation through 180 it is brought to a standstill by the brake, whereupon the slide valve 59 is returned into its middle position. With the slide view in this position both chambers of the cylinder 44 are in communication with the oil sump 56. The helical spring 45 is therefore now able to thrust the hollow shaft 41 towards'the left until its collar 52 once more rests in contact with the stationary bearing 48. This brings the bending tool 20 back to a 6 working position, the bending tool now however being on the other side of the wire. I e

After completion of all the necessary bending operations the wire is cut off between the two shear blades 17, 18. The drive for the shears is essentially similar to the other two drives, for advancing the wire and for the bending mechanism. An electric motor 62 transmits drive through a V-belt 63 to a flywheel 64 which can be coupled to a gearwheel 65 which engages with a gearwheel 66 which drives the mobile shear blade 18 through an eccentric 67 and a connecting rod 68.

When the wire has been cut, the electro-hydraulic slide valve 59 is moved into the position crossed flow paths. This has the result that the piston 43 in the cylinder 44 is thrust towards the left, in the direction of the arrow b. The piston rod 42 thrusts the ejector rod 51 in the interior of the hollow shaft 41 towards the left, the pin 49 sliding towards the left in the longitudinal slots 50 in the wall of the hollow shaft, the pin sliding thesleeve 47 to the left over the surface of the hollow shaft 41, compressing the helical spring 45. In this movement the ejector rod 51 ejects the finished loop out of the gap between the two stationary bending anvils 19 and 19a. Finally, after the electro-hydraulic slide valve 59 has been returned to its neutral position, the helical spring thrusts the ejector rod back into its position of rest.

In the modification represented in FIGS. 4 and 5, the mobile bending tool 20 is driven by a, preferably hydraulic, pressure applied to a piston in a cylinder 81. Hydraulic control can be provided by means of a slide valve, as already described. This need not be discussed in detail again at this point. -A piston rod 82 is pivoted at 83 to a gearwheel39 which is permanently engaged with a gearwheel 40 fixed to the bending tool 20, as already described for the FIGS. 1 to 3 example. The bending angle is determined by a stop-bar 85 fixed to the gearwheel 39 and cooperating with adjustable counter-stops 84, 84a. It will be observed that this arrangement doesno provide any facility for automatically adjusting the bending angle during operation of the machine. This kind of adjustability is a special advantage of the driving mechanism represented in FIGS. Ho 3.

.The versions of the invention described above all use a bending device whose principle of operation is represented diagrammatically in FIG.'6. Two stationary bending anvils 19 and 19a are positioned on each side bent. A mobile bending tool positioned at the location 20 in FIG. 6, on one side of the path B, cooperates with the stationary bending anvil 19, bending the wire by swinging around into the position 20' on the other side of the path B. In the next bending operation the mobile bending tool cooperates with theother stationary bending anvil 19a. On the other hand, as shown in FIG. 7, there can if desired be used only a single stationary bending anvil 19 cooperating with a mobile bending tool 20. In this case to change the direction of bending the two parts 19 and 20 both move across into new positions 19, 20 on the other sides of the path B.

A simple construction based on the principle represented in FIG. 7 is shown diagrammatically in FIG. 8. A bending anvil 19 in the form of a roller is mounted rotatable on a shaft 102 to which is fixed a pinion 101 which engages with a rack bar 100. A link 103 connects the shaft l02 to a bending tool 20. The shaft 102 is mounted-to slide on a vertical guide 104, drive in this sliding movement by a hydraulic piston which is not shown in the drawing. The changing of the bending direction is effected as follows. After retraction of the parts 19, 20, out of the way of the path B, the shaft 102 is slid vertically downwards on the guide 104, powered by the hydraulic piston, from the position shown in full .lines in FIG. 8, above the path B, into the position shown in broken lines under the path B, the rack bar 100 remaining stationary. During this movement the pinion 101 rolls along the rack bar 100, the link 103 swinging around anticlockwise, lifting the bending tool into a position above the path B. The bending action is obtained by moving the rack bar 100 in the directions P1, P2 with the shaft 102 held stationary. This swings the link 103 clockwise or anticlockwise, the bending tool 20 moving from the broken line position to the full line position or vice versa.

Numerous other driving mechanisms are of course possible, within the frame of the invention, for exchanging the positions of one or both of the bending anvils and tools. I

We claim:

1. A machine for bending wire or strip, said machine comprising means for intermittently advancing raw material for bending along a path, step by step, the length of each step being the desired distance between two successive bends, a stationary anvil, ane an intermittently driven mobile bending tool which bends said wire or strip through a desired angle around said anvil; an improved mounting for said bending tool comprising means for retracting said bending tool from a working position on a selected one side of said path, means for moving said retracted bending tool to the other side of said path without intersecting said path, and means for advancing said bending tool to a working position on said other side of said path whereby said single bending tool is adapted to bend said wire or strip selectively in either of two opposite bending directions away from said path.

2. A machine according to claim 1, wherein there are two stationary bending anvils positioned one on each side of said path, said bending tool co-operating selectively with one or other said two anvils for bending said wire or strip in one of two said directions.

3. A machine according to claim 2, wherein said two anvils are positioned symmetrically, one on each side of said path and said bending tool is mounted on a crank, there being means oscillating said crank about an axis intersecting said path.

4. A machine according to claim 3, wherein said crank has a shaft supportingsaid bending tool and an ejector rod for bent wire or strip slides independently within said shaft.

5. A machine according to claim 1, wherein a single bending anvil is provided for bending said wire or strip in both of said directions, said anvil having means re tracting said anvil from a working position on one side of said path, means moving said anvil to said other side of saidpath without intersecting said path, and means advancing said anvil to a working position on said other side of said path.

6. A machine according to claim 5, wherein said anvil and said bending tool are both mounted on a common link, there being means pivotally mounting said common link about an axis intersecting said path for the purpose of shifting said anvil and said bending tool to alternate sides of said path, and means adapted to swing said link about said anvil after the manner of a crank for making a bend.

1' UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 823 ,749 Dated July 16 1974 lnventor( Josef et a].

It is certified that errorappears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the title page Item [56] after the German reference q document there should be added:

. Britain...... 00

In claim 1, 5th line (line 28 of col. 7) "ane" should d read --and- Signed and Scaled this Seventeenth D3) of August 1982 [SEAL] d Attcsl:

GERALD J. MOSSINGHOFF Arresting Offl! Commissioner of Patenls and Trademarks 

1. A machine for bending wire or strip, said machine comprising means for intermittently advancing raw material for bending along a path, step by step, the length of each step being the desired distance between two successive bends, a stationary anvil, ane an intermittently driven mobile bending tool which bends said wire or strip through a desired angle around said anvil; an improved mounting for said bending tool comprising means for retracting said bendiNg tool from a working position on a selected one side of said path, means for moving said retracted bending tool to the other side of said path without intersecting said path, and means for advancing said bending tool to a working position on said other side of said path whereby said single bending tool is adapted to bend said wire or strip selectively in either of two opposite bending directions away from said path.
 2. A machine according to claim 1, wherein there are two stationary bending anvils positioned one on each side of said path, said bending tool co-operating selectively with one or other said two anvils for bending said wire or strip in one of two said directions.
 3. A machine according to claim 2, wherein said two anvils are positioned symmetrically, one on each side of said path and said bending tool is mounted on a crank, there being means oscillating said crank about an axis intersecting said path.
 4. A machine according to claim 3, wherein said crank has a shaft supporting said bending tool and an ejector rod for bent wire or strip slides independently within said shaft.
 5. A machine according to claim 1, wherein a single bending anvil is provided for bending said wire or strip in both of said directions, said anvil having means retracting said anvil from a working position on one side of said path, means moving said anvil to said other side of said path without intersecting said path, and means advancing said anvil to a working position on said other side of said path.
 6. A machine according to claim 5, wherein said anvil and said bending tool are both mounted on a common link, there being means pivotally mounting said common link about an axis intersecting said path for the purpose of shifting said anvil and said bending tool to alternate sides of said path, and means adapted to swing said link about said anvil after the manner of a crank for making a bend. 